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Re: [E1000-devel] Question on igb and rx-fcs.
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From: Wyborny, C. <car...@in...> - 2012-02-24 20:30:31
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>-----Original Message----- >From: Ben Greear [mailto:gr...@ca...] >Sent: Tuesday, February 21, 2012 4:30 PM >To: Wyborny, Carolyn >Cc: e1000-devel list >Subject: Re: [E1000-devel] Question on igb and rx-fcs. > >On 02/21/2012 04:23 PM, Wyborny, Carolyn wrote: >> >> >>> -----Original Message----- >>> From: Ben Greear [mailto:gr...@ca...] >>> Sent: Tuesday, February 21, 2012 10:09 AM >>> To: Wyborny, Carolyn >>> Cc: e1000-devel list >>> Subject: Re: [E1000-devel] Question on igb and rx-fcs. >>> >>> On 02/21/2012 09:51 AM, Wyborny, Carolyn wrote: >>>>> -----Original Message----- >>>>> From: Ben Greear [mailto:gr...@ca...] >>>>> Sent: Monday, February 20, 2012 3:09 PM >>>>> To: e1000-devel list >>>>> Subject: [E1000-devel] Question on igb and rx-fcs. >>>>> >>>>> I'm trying to write a patch to allow rx-fcs on the igb driver >>>>> (82580 chipset). >>>>> >>>>> I tried the patch below, but when I then enable rx-fcs, traffic >>>>> rx breaks and I see Rx-FIFO error counts increasing. I'm testing >>>>> with 1024 byte UDP payloads, at 56kpbs. >>>>> >>>>> First, if anyone sees an obvious problem with the patch, please >>>>> let me know...but more importantly, what developer's manual >>>>> is valid for the igb supported hardware? I found the '316080.pdf' >>>>> that seems valid for e1000e, but I'm not sure it works for igb >>>>> as well? >>>> [...] >>>> >>>> The hardware can behave differently for a given feature and the igb >>> drivers supports a different set of hardware than e1000e. For igb, >we >>> support 82575 and greater (82576, 82580, i350). The best bet is the >>> Datasheet for the 825XX you're working with. Here's the datasheet >for >>> 82580. http://download.intel.com/design/network/datashts/321027.pdf. >>> I'll take a look at your patch and the datasheet as well and see if I >>> can find anything to help. >>> >>> Thanks for the datasheet pointer. >>> >>> I did a quick search for SECRC, and section 8.8.2.7 mentions the >SECRC >>> bits are >>> ignored if some virtual machine logic is enabled. I'm not using any >>> virtual >>> machines, but perhaps that logic is enabled anyway? >>> >> [..] >> Yeah, it shouldn't be enabled though if you aren't configuring the >virtualization nor using a virtualized os. Hmm.., seems that >rx_fifo_errors is an accumulation stat and I think there's also a typo >in that spec as it lists a stat that doesn't exist anywhere else in the >document. I'll dig around a bit more on this, but basically, as you can >probably see, you're dropping those packets. If you set the RCTL_SBP >bit in the driver, you can accumulate the different errors and see >exactly what is going wrong there. I could give you a patch to do that. >Are you using upstream in kernel version or a standalone version of the >igb driver? > >I already wrote a patch to do SBP part, and will post it and the ones >for ixgbe after we do some more internal testing. > >And, I no longer see the rx-fifo errors after I properly reset the chip >when enabling the 'rx-fcs' logic. (In the patch I posted, I was just >twiddling >the register in the set_features() method, which appears to be a bad >idea). > >But, though I receive packets just fine, I do NOT see the 4 bytes of FCS >on >the end. > [..] I checked around a bit and there's no reason I can see why this isn't working, so I raised the issue with our internal hw support team. I'll let you know what I find. There's nothing much to do here in sw, but make sure that bit is unset, rest is up to the hw. If you're seeing this with e1000e, then I assume your sniffer setup is identical and correct. Thanks, Carolyn Carolyn Wyborny Linux Development LAN Access Division Intel Corporation |